It is known to provide an artificial airway device in the form of a laryngeal mask comprising an airway tube opening into the interior space of a mask portion which is positioned in the hypopharynx of the patient and forms a seal around the inlet to the larynx to form an airway to the patients lungs permitting spontaneous or controlled ventilation thereof.
Such a known artificial airway device suffers from several disadvantages. As the mask portion has to provide a seal around the inlet to the patients larynx, it is necessary for the mask to be formed with a collar engaging in sealing contact with the tissues around the circumference of the patients laryngeal inlet, resulting in the need for the mask portion to be of a relatively large size and complex shape.
The complexity of the shape of the mask portion is further increased by the need to provide restraining means extending across the open space defined by the collar to reduce the risk of a blockage to the airway by the epiglottis falling inwards into said open space.
The size and complexity of shape of the mask portion of this known type of artificial airway device makes it difficult and expensive to produce. In order for this known type of artificial airway to be economically viable in view of its cost, it is therefore necessary to produce the device from materials which allow the device to be re-used which further increase the cost of the known device.
The re-use of such devices is in itself inherently inadvisable due not only to the possibility of eventual failure of parts of the device during use but also to the danger of cross-infection between patients if the device is not completely sterilised prior to re-use.
A further disadvantage of the known device is that the complexity of the shape of the mask portion in particular makes it difficult to ensure that the device is effectively sterilised.
Another disadvantage of the known device results from the need for the mask portion thereof to engage in sealing contact with the tissues around the circumference of the patients laryngeal inlet, resulting in the need for the mask portion to be accurately positioned and the risk of this portion of the device being wholly or partially dislodged during movement of a patient during an operation which can cause difficulties in maintaining said sealing contact.
Yet another disadvantage of the known device is that access to the oesophagus is precluded or at least severely restricted by the mask portion of the known device and the relatively large size of the mask portion of the known device only permits oral introduction into the patients hypopharynx and precludes nasal introduction of the device which may be required for certain operations involving for example dental surgery.